Exhaust is a major contributor to the overall sound level of trucks and off-road vehicles. One common form of muffler which has been used in the past in conjunction with vehicle exhaust systems is the plug-type in which the inner end of the exhaust inlet tube is plugged or blocked off, thereby causing the exhaust gas to flow radially outward through perforations in the inlet tube and then flow longitudinally along the inner wall of the body to the outlet tube for discharge to the atmosphere.
Floating baffles or flanges have been used in the past in conjunction with plug-type mufflers to define sound attenuating chambers within the muffler body. With this construction, the baffle is secured around the inlet or outlet tube and the peripheral edge of the flange is unattached to the body.